12AX7 preamp tubes play a remarkable, dynamic role in the creation of the final tone in your vacuum tube amplifier. 12AX7s are components, early in the circuit, that determine how clean or, how lush, layered and massive the high gain will be not to mention all the tonal shades of grey in between like clipped, overdriven and crunch sounds. MESA 12AX7s provide the stability AND high gain required for extraordinary distortion sounds while at the flick of a switch, deliver the sensitivity and brilliance needed for some of the world's most detailed, crisp clean sounds as well as the subtleties of the in between gain ranges.

MESA preamp tubes are among the highest quality available and selected for their exceptional full-range tonal quality, stability, low noise and low microphonics. They provide the maximum level of high gain output with low sensitivity to microphonic noise while producing a balanced response across the tonal spectrum that is extremely lively, open and expressive. All MESA tubes offer unsurpassed consistency and reliability for ANY tube amplifier, and certainly MESA amplifiers!